This invention relates generally to galvanic cells, and particularly to galvanic cells of the type employing thionyl chloride as an inorganic electrolytic solvent.
Thionyl chloride is well known as an inorganic electrolytic solvent for galvanic cells. This use is described, for example, on page 234 of Non-Aqueous Solvents (1953) by Audrieth and Kleinberg.
Although thionyl chloride has the attribute of being an inorganic solvent in which a large number of salts of diverse compositions may be dissolved, it also can be readily reduced like other oxychlorides at the cathode surface of a galvanic cell, thus acting as a cathodic depolarizer as well as a solvent. In high rate applications, however, electrolytes using pure thionyl chloride as solvent fail to yield high coulombic efficiencies in cells using lightweight metals, e.g., lithium as anodes.
Accordingly, it is a general object of the present invention to provide an improved galvanic cell employing thionyl chloride as an electrolytic solvent.
More specifically, it is an object of the invention to provide an improved galvanic cell comprising an anode composed of one or more relatively light weight metals less noble than zinc, and an electrolytic solvent including thionyl chloride.
Other objects of the invention are to provide a galvanic cell employing a metal less noble than zinc such as lithium as an anode, and an electrolytic solvent including thionyl chloride, which cell is relatively stable and develops high coulombic efficiencies.